JP5447866B2 - Lithium bis (oxalato) borate (LiBOB) that is crystalline and completely soluble - Google Patents

Description

  The subject of the present invention is the crystalline and completely soluble lithium bis (oxalato) borate (LiBOB), its production process and the use of lithium bis (oxalato) borate.

  Lithium batteries are used as an energy storage, especially for applications in portable electronic devices (so-called laptops, mobile phones), based on high energy density and power density compared to other types of batteries The A distinction is made between primary batteries which have a lithium metal anode and which cannot be recharged, and secondary batteries (lithium accumulators), ie rechargeable batteries.

Both types of batteries contain an anhydrous liquid or gel ion-conducting electrolyte, in which a conductive salt such as LiPF ₆ , LiBF ₄ , lithium imide, lithium methide or lithium borate Salts such as lithium bis (oxalato) borate (LiBOB, corresponding to Li [B (C ₂ O ₄ ) ₂ ]) are present in dissolved form.

Salts of lithium borate, such as LiBOB, provide significant improvements in cycle stability and safety compared to elemental lithium fluorides such as LiPF ₆ or LiBF _{4 in} lithium secondary batteries (Cox, S., et al. S. Zhang, U. Lee, J. L. Allen, T. R. Jow, J. Power Sources 46, 2005, pp. 79-85). This is due to a change in the form of the protective layer formation on the carbon anode of the lithium battery. That is, the borate electrolyte forms a thin and extremely stable Li ⁺ conductive layer on this anode, which is also stable at high temperatures and is therefore dangerous between the charged anode and, for example, the electrolyte. Decomposition reaction is prevented (J.-C. Panitz, U. Wietelmann, M. Wachtler, S. Strebelle, M. Wolfahrt-Mehrens, J. Power Source, 153, 2006, pp. 396-401, Broschere. Chemetall 2005). Improvements with borates in the protective layer create new possibilities for electrolyte preparations for the applicator. Thus, for example, it is possible to give up ethylene carbonate (1,3-dioxolan-2-one) which is difficult to handle, and use propylene carbonate (4-methyl-1,3-dioxolan-2-one) instead. (K. Xu, S. Zhang, R. Jow, J. Power Source 143, 2005, pp. 197-202). In addition, it is possible to abandon the 1,3-dioxolan-2-one compound completely and use γ-lactone, for example γ-butyrolactone instead (US-A-2007 / 0065727).

DE-C-19829030 discloses a series of methods for producing LiBOB:
1. Reaction of lithium borohydride with succinic anhydride:

The disadvantage is that, besides the high LiBOB price, side reactions occur, during which the oxalic acid or oxalate ions are attacked and reduced by the hydride.
2. Reaction of lithium hydroxide or carbonate with boric acid or boron oxide and oxalic acid in aqueous solution and subsequent drying of the product, for example:

A variation of this reaction implementation is to react two of the three raw material components first and then perform LiBOB synthesis for the first time, for example:

Other suitable raw materials are LiHC ₂ O ₄ or LiBO ₂ .
3. 1. in an organic solvent such as toluene. Removal of the water formed by reaction of the raw materials described in 1. and azeotropic distillation.
4). Reaction of lithium alkoxides and boric acid esters with succinic anhydride in solvents such as alcohols:

  Finally, it is known from DE-C-1018608 that the reaction described in (2) is carried out in a heterogeneous phase without adding water or other solvents.

Common to all of the above methods is that LiBOB does not occur in a sufficiently pure form. LiBOB is contaminated with various amounts of water, acidic components and insoluble byproducts such as lithium oxalate (Li ₂ C ₂ O ₄ ) or lithium carbonate (Li ₂ CO ₃ ). Thus, when a crude salt of LiBOB is dissolved in an aprotic solvent such as an ester or nitrile, a very turbid solution is formed. The proportion of insolubility is generally 0.5-2% by weight, and the homogenized solution has a turbidity exceeding 100 NTU (NTU = turbidimetric turbidity unit), generally 200-1000 NTU. .

  For this reason, LiBOB crude salt needs to be subjected to a purification step. According to the prior art, this occurs by recrystallization from acetonitrile (AN). For this, first a saturated clear LiBOB solution in acetonitrile is prepared, and then toluene is added. Toluene displaces LiBOB from the solution, and a needle-like crystal composed of a LiBOB / AN complex containing AN is formed as a solvate. The complex is subsequently vacuum dried, for example at 80 ° C. for several days (W. Xu, C.A. Angell, Electrochem. Solid-State Lett. 4 (2001), E1-E4). In this drying procedure, the bound AN is removed, in which case the crystalline form is destroyed. The LiBOB thus formed, which is substantially free of solvates, is obtained in a very fine and difficult to handle form. Similarly, LiBOB is crystallized in the form of a solvate from many other solvents such as tetrahydrofuran (THF) or ethyl acetate. All of these solvents are not conventional or desirable in batteries and must be completely removed before use. At the same time, as in the case of AN, a fine, hygroscopic powder is produced, which is very difficult to handle.

  Furthermore, it is difficult to completely remove the last solvent residue. It is known from ethyl acetate that it can interfere with the high temperature stability of lithium ion batteries even at relatively low concentrations (TR Jow, K. Xu, MS Ding, SS Zhang. JL Allen, K. Amine, J. Electrochem. Soc. 151, A1702-A1706 (2004)).

  The object of the present invention is to overcome the drawbacks of the prior art.

  A particular object of the present invention is to provide LiBOB crystals that do not contain solvents that are foreign to the battery, in particular no acetonitrile, are completely soluble and at the same time less dusty. Completely soluble means in the sense of the present invention in this case that the turbidity of a solution of approximately 15% LiBOB in acetonitrile is at most 100 NTU, preferably at most 50 NTU. In the sense of the present invention, “small dust” means that the dust ratio is less than 10% by mass in this case. Dust in the sense of the present invention means particles whose maximum diameter is smaller than 10 μm.

  According to the invention, the problem is surprisingly solved by LiBOB having the features of claim 1. Advantageous embodiments are described in the dependent claims.

The solution according to the invention of the above problem is surprisingly in the form of a crude crystalline, substantially rectangular parallelepiped, the average value of the maximum diameter of the primary crystals being 50 μm to 5 mm, preferably 200 μm to 2 mm, in particular The object is to provide LiBOB which is preferably 500 μm to 1 mm. Advantageously, less than 20% by weight of LiBOB is less than half the average value. Average volume of the primary crystals, 0.01~100mm ^3, advantageously 0.1 to 50 mm ^3.

  According to the invention, the dust proportion is less than 10% by weight, preferably less than 5% by weight, particularly preferably less than 2% by weight.

  LiBOB produced according to the present invention dissolves in an aprotic solvent, for example, in a carbonate solvent, ester or acetonitrile, leaving almost no residue. The insoluble residue is at most 0.1% by weight, preferably at most 0.01% by weight. The solution is clear or in any case slightly turbid. The turbidity of a solution of LiBOB according to the invention of about 15% in acetonitrile is at most 100 NTU, preferably at most 50 NTU.

  According to the invention, LiBOB contains a cyclic 5-membered ester as an essential component for purification, in particular for recrystallizing the crude LiBOB salt, or uses a solvent consisting of this ester. It is obtained by the method to do. In this case, the cyclic 5-membered ring ester according to the present invention is a 1,3-dioxolan-2-one compound, or a plurality of 1,3-dioxolan-2-one compounds or γ-lactones or a plurality of γ-lactones or the aforementioned A mixture of at least two compounds.

  LiBOB according to the present invention is a LiBOB. (N5-membered ring ester) complex with a 5-membered ring ester selected according to the present invention as a solvate (where n represents the number of moles of 5-membered ring ester relative to LiBOB (LiBOB Mole number = 1)). The number of moles n is 0.001 to 10, preferably 0.01 to 5, particularly preferably 0.1 to 3, particularly preferably 0.2 to 2 equivalents, depending on the performance of the process. It's okay. In a special embodiment of the invention, n = 0, ie LiBOB contains no solvate.

  According to the invention, LiBOB preferably has a residual solvent proportion of less than 50% by weight.

  Preference is given to ethylene carbonate (EC, 1,3-dioxolan-2-one), propylene carbonate (PC, 4-methyl-1,3-dioxolan-2-one) or butylene carbonate (BC, 4-ethyl). 1,3-dioxolan-2-one). The γ-lactone is preferably selected from γ-butyl lactone or γ-valerolactone.

  When the LiBOB according to the invention contains a solvate, this solvate consists only of the 5-membered ring ester itself selected according to the invention. According to the present invention, LiBOB contains no solvate other than the five-membered ring ester selected according to the present invention and in particular does not contain acetonitrile (no AN).

  The solvent selected according to the invention may further contain another or more other aprotic solvents that do not form solvates with LiBOB, such as hydrocarbons, ethers, Selected from esters or acyclic carbonates.

  Advantageously according to the invention, the solvent selected according to the invention is a 1,3-dioxolan-2-one compound or γ- having a normal purity in commercial products and a water content of less than 0.5% by weight. Made of lactone.

  The method according to the invention can be carried out in several variants. First, a LiBOB solution is produced in a solvent selected according to the present invention. For this purpose, the LiBOB crude salt produced in a manner known per se is introduced into the solvent selected according to the invention in an amount corresponding to the maximum saturation concentration, with the exclusion of air and moisture. If LiBOB is to be subsequently crystallized from solution, it is advantageous according to the invention to produce a nearly saturated solution (ie the LiBOB solution has at least 90% of the maximum LiBOB concentration). In the case of EC and PC, this is about 16-20% by weight of LiBOB. The dissolution process can be aided by suitable homogenization measures according to the prior art, for example by stirring or shaking and optionally heating, for example heating to a temperature of 30-100 ° C.

  Alternatively, a solution having a lower concentration of the LiBOB crude salt in the solvent selected according to the present invention, for example, a solution having a concentration of 5 to 15% by mass, may be added. This is advantageous if it is desired to obtain a nearly anhydrous LiBOB solution in which the water content should be less than 500 ppm, preferably less than 200 ppm.

  LiBOB crude solutions produced using solvents selected according to the present invention are generally hazy. This is due to the use of LiBOB crude salt produced by the prior art. Since this turbidity is unacceptable for lithium battery applications, insoluble components must be removed from the solution by conventional techniques such as filtration, decantation and / or centrifugation. Preference is given to a membrane filtration method, in which case a solvent-resistant membrane of 0.5 μm or less, preferably 0.2 μm or less, is particularly preferably used.

  A solution of LiBOB in a solvent selected according to the invention, obtained by solid-liquid separation, completely clear and optionally deacidified and / or dried by one or more further pretreatment steps According to the invention, it can be post-treated into dust-free crystals by three variants. For this purpose, the present invention advantageously uses a nearly saturated LiBOB solution.

  A) Crystallization by evaporation: the LiBOB solution is evaporated and concentrated under reduced pressure (preferably 0.01 to 100 mbar) and at a bottom temperature of up to 200 ° C., when a saturation concentration is exceeded. Also, LiBOB containing no solvate is precipitated in the form of crystals. In order to avoid the formation of a solid LiBOB solvate complex, the temperature during crystallization must be higher than the decomposition temperature of the solvate. Surprisingly, only LiBOB containing no solvate was crystallized at the bottom temperature of 80 ° C. or higher.

  B) Substitution crystallization: in a LiBOB solution, 0.01-5, preferably 0.1-3, of a 5-membered cyclic ester containing LiBOB as a complex, for example in a solvent according to the invention as a solvate Particularly preferably, an organic solvent or solvent mixture which does not dissolve LiBOB is added until it precipitates as a complex having 0.2 to 2 equivalents, and the mixture is homogenised, for example stirred or shaken. As organic displacement solvent, preferably aromatic hydrocarbons such as toluene, ethylbenzene or xylene or saturated hydrocarbons such as pentane, hexane, heptane, cyclohexane or methylcyclohexane or fully or partially fluorinated hydrocarbons or Ethers such as diethyl ether, di-n-propyl ether, dibutyl ether, diisopropyl ether, methyl-t-amyl ether or methyl-t-butyl ether or mixtures of these solvents are used. The substitution solvent is added in an amount of 30 to 300% by volume based on the volume of the charged LiBOB solution. This addition is carried out at 0 to 100 ° C., preferably at 0 to 60 ° C. In a particularly advantageous embodiment, the displacement solvent can be added in multiple portions. After each addition, waiting for the equilibrium to be adjusted between the two liquid phases formed, the upper, low LiBOB phase is removed, for example by decantation. In this way, almost complete replacement of LiBOB from the solution phase can be achieved. In this case, a particularly high yield of LiBOB · (n5-membered ring ester) complex as crystals is achieved.

  C) Cold crystallization: LiBOB solution is stored at a low temperature, for example at 0 ° C. The resulting crystals are LiBOB • 5-membered ring ester complexes, which can be separated from the mother liquor, for example by filtration. It is advantageous to produce a saturated LiBOB solution at 40 to 150 ° C. and to cool it to a temperature of −20 ° C. to + 20 ° C. In order to carry out the crystallization completely, the solution is stored at a low temperature for at least 10 minutes, preferably at least 2 hours, particularly preferably 2 to 10 hours, and then the LiBOB. (N5-membered ring ester) complex is crystallized. Isolated as

  According to the invention it is also possible to combine individual crystallization techniques. For example, the displacement solvent can be added at a high temperature, for example at 50 ° C., and cooled after mixing, for example to 0 ° C. A variant of substitution crystallization B) is to charge the LiBOB solution and add the substitution solvent without homogenization, ie cover the LiBOB solution with a solvent of low specific gravity. Since mixing is only carried out by diffusion and thus only very slowly, a correspondingly large defect-free LiBOB · (n5-membered ring ester) complex is formed as a crystal, which corresponds to the corresponding crystal. Particularly high purity.

  According to the invention, crystallization by evaporation is preferred. This makes the method particularly economical since this technique gives up the second solvent. However, a special advantage is that such a method can provide a surprisingly solvent-free and solvate-free LiBOB. The residual solvent content is less than 2% by weight. Only in such a provision form the end user has complete freedom in the liquid electrolyte composition. Since the solvent applied according to the present invention is a substance commonly used for battery applications, 1,3-dioxolan-2-one compound or γ-lactone, the residual content of the remaining solvent is not a problem at all.

Particularly surprising to the person skilled in the art is the fact that LiBOB free of solvates can be produced by crystallization by evaporation concentration. The five-membered ring ester selected according to the invention is thus a very strong Lewis base, which, as is known from LiBOB and acetonitrile, THF, ethyl acetate and other solvents, correspondingly forms a solid complex. Form. Below is a comparison of the dipole moments of the various solvents. These physical constants correlate with Lewis basicity:

It has been found that the LiBOB. (N5-membered ring ester) complex formed during substitution crystallization or cooling crystallization is actually stable. FIG. 1 illustrates this based on thermogravimetric analysis using an example of LiBOB · 2EC complex at a heating rate of 10 K / min:
Ordinate: temperature (℃),
Abscissa: time in minutes.

  However, LiBOB crystals with a high content of 5-membered cyclic esters selected according to the invention are also embodiments according to the invention. The five-membered ring ester according to the invention is in this case bound to LiBOB by electrostatic interaction, i.e. a solid solvation complex is present. The exact composition of the solvate complex, i.e. the molar ratio of LiBOB to 5-membered ring ester, can vary significantly, with each pressure / temperature condition during crystallization and the 5-membered ring used each time. Arises from the material properties of the ester.

  Conventional or market electrolytes for lithium ion batteries contain at least one solvent based on 1,3-dioxolan-2-one compounds, often ethylene carbonate or γ-lactone. As such, the solvates are often used directly for battery electrolytes without having drawbacks.

  LiBOB produced by the process according to the invention occurs in a coarse crystalline, dust-free form. This applies to both LiBOB containing no solvate and LiBOB · 5-membered ring ester complex. Surprisingly, for LiBOB solvate complexes produced according to the prior art, these are very stable and can be made into a dry, fluid form, for example at a moderate temperature of 20- The 5-membered cyclic ester selected according to the invention is not lost during drying at 60 ° C. That is, the LiBOB • (n5-membered ring ester) complex produced by the method according to the present invention does not decompose into a powder as in the case of the LiBOB • solvate complex produced by the method according to the prior art.

  In a particularly advantageous embodiment of the process according to the invention, the solution of the crude LiBOB salt produced in the first step in the solvent selected according to the invention, which is still turbid, is insoluble in the solvent selected according to the invention. Pretreatment with a basic compound or a solid which removes water, which is also insoluble in the solvent selected according to the invention. Alkali metal hydrides as basic compounds, preferably sodium hydride and / or lithium hydride, metal oxides, preferably calcium oxide, lithium oxalate, lithium hydrogen oxalate, lithium metaborate, lithium tetraborate, lithium carbonate Alternatively, anhydrous lithium hydroxide or a mixture of the above substances can be used. Molecular sieves and / or aluminum oxide are used as the solid from which water is removed.

  This pretreatment takes place in a closed apparatus with exclusion of air and moisture. These substances can be used alone or in combination to reduce the water and acid content of the LiBOB crude salt solution. These are generally added in an amount of 0.01 to 10% by weight of the LiBOB solution. It is advantageous to homogenize the resulting suspension, ie, for example, to stir and / or shake. In many cases, it is recommended to perform this process at elevated temperatures, generally 30-200 ° C. Depending on the pretreatment agent, its concentration and temperature, the working time is 10 minutes to 1 week, preferably 1 hour to 20 hours. The purified suspension is then clarified by solid-liquid separation as described above.

  Another possibility for drying the LiBOB crude salt solution in the solvent according to the invention is to distill off the water in the course of partial solvent removal. For this purpose, the LiBOB solution is preferably heated under vacuum and a part of the solvent is distilled off. Surprisingly, it has been found that in this way the contained water can be evaporated at least partly together. In this variant, preferably a diluted solution of LiBOB crude salt in a solvent selected according to the invention, for example a solution having a concentration of 5 to 15% by weight, is used. Thus, crystallization of LiBOB or LiBOB solvate complex can be avoided. Advantageously, the solvent according to the invention does not contain a solvent component that boils at temperatures below about 200 ° C. at standard pressure. Particularly preferably, the solvent selected according to the invention consists only of the 5-membered cyclic ester selected according to the invention. When starting from a LiBOB solution containing 500 to 5000 ppm of water, a residual water content of generally less than 200 ppm, preferably less than 100 ppm, can be achieved by the drying process according to the invention.

  In order to avoid LiBOB from decomposing during distillation, the distillation temperature should not exceed 200 ° C. The distillation is preferably carried out in the temperature range from 80 to 170 ° C. This distillation step, combined with the concentration of LiBOB, is preferably carried out under reduced pressure, particularly preferably at about 50 mbar.

  The purified LiBOB solid produced in accordance with the present invention or a solution of LiBOB in an aprotic solvent is used as an electrolyte or electrolyte component in an electrical component, for example a lithium ion battery.

The figure which shows the analysis result based on the thermogravimetric analysis method of LiBOB * 2EC Figure showing a crystal according to the invention by means of a scanning electron microscope Figure showing a crystal according to the invention by means of a scanning electron microscope The figure which shows the crystal by the comparative example with the scanning electron microscope

  The following examples illustrate the invention in detail but do not limit the invention. In all tests, membrane filtered (fluoropolymer, DSS / Alfa Laval, pore size 0.15 μm) LiBOB solution was used, where LiBOB was produced according to DE-C-19839030.

Example 1: Production of LiBOB crystals containing no solvates (crystallization by evaporation, separation of crystals at about 100 ° C.)
5064 g of a LiBOB 17% solution having a water content of 230 ppm in propylene carbonate (PC) was evaporated at about 8-10 mbar and about 120 ° C. After distilling off about 0.8 kg of PC, the vacuum was interrupted for a short time and 1 g of LiBOB crystals according to the invention was added. During the subsequent vacuum distillation, the LiBOB solution became turbid. A total of 2.34 kg of PC was distilled off.

  The vacuum was interrupted and the resulting suspension was cooled to 110 ° C. with stirring. The suspension was then discharged into a heatable sintered glass filter and filtered. The filtration time was about 3 minutes. The crystals were washed three times with 100 ml of preheated toluene each time and vacuum dried at a temperature of 80-90 ° C.

Yield: 382 g of crude crystals,
Li ⁺ (ICP): 5.15 mmol / g (≈99.8% of the theoretical value),
Water content: not detectable ( ¹ H-NMR method),
Stability: decomposition started at> 300 ° C. (thermogravimetric analysis),
Purity: free of detectable impurities in ¹¹ B-NMR spectrum (solution in CD ₃ CN),
SEM: a rectangular parallelepiped crystal having a maximum edge length of about 0.2 mm (see FIG. 2).

  The crystals dissolved in acetonitrile without leaving a residue completely (clear solution). The PC residual content was less than 0.2% by mass. The proportion of dust is less than 1%.

Example 2: Production of LiBOB.0.2PC solvate (crystallization by evaporation and concentration, separation of crystals at room temperature)
639 g of a 16.1% solution of LiBOB in propylene carbonate (PC) was charged into a dry 1 liter Schlenk flask charged with argon and about 30 mbar and oil bath temperature 150-160 ° C. using a rotary evaporator. And concentrated by distillation. After distilling off 170 g of PC, crude crystals began to precipitate. A total of 236 g of PC was distilled off. It was then cooled to room temperature and the batch was stored at this temperature for 1 day. The crystals were isolated by filtering through a reverse flow sintered glass filter. After washing twice with methyl-t-butyl ether, the crystals were vacuum dried at room temperature for 4 hours.

Yield: 20g
Li ⁺ (ICP): 4.80 mmol / g (≈LiBOB 93%, balance PC),
Water content: 250 ppm,
Thermogravimetric analysis: 9.2% mass loss (≈LiBOB · 0.19PC) at 300 ° C.
Purity: free of detectable impurities in ¹¹ B-NMR spectrum (solution in CD ₃ CN),
SEM: A rectangular parallelepiped crystal having a maximum edge length of about 0.5 mm (see FIG. 3).

  The product without dust (dust percentage less than 1%) was found to be completely soluble in acetonitrile.

Example 3: Production of LiBOB / 0.4PC solvate (substituted crystallization)
300 g of a clear solution of 17.0% LiBOB in propylene carbonate was coated with 560 g of toluene under stirring. By the end of the toluene addition, a colorless solid began to crystallize in the lower liquid phase. The agitator was stopped and the upper toluene-enriched phase was separated by decantation (550 g, with a Li ⁺ content of 0.057 mmol / g). The stirrer was then started again and 340 g of fresh toluene was added. In so doing, much more crystals were formed and the heavier liquid phase disappeared.

  This was cooled to 0 ° C. and maintained at this temperature for 2 hours. The cold mixture was then filtered. The crystals were washed twice with 50 ml of toluene each time and then dried in vacuo for 5 hours at room temperature.

  40.2 g of colorless crystals having a lithium and boron content of 4.2 mmol / g were obtained. This value corresponds to a LiBOB content of 81%, ie a LiBOB · 0.43PC complex.

  Yield: 64% of theory.

  The LiBOB solvate was completely dissolved, leaving no residue in acetonitrile, and having a proportion of dust of less than 1% by weight.

Example 4: Pretreatment (predrying) of LiBOB / PC crude solution with aluminum oxide
11.2 kg of a 17.0% solution of LiBOB having a water content of 470 ppm (Karl Fischer titration) in PC was stirred for 5 hours with 538 g of aluminum oxide (Alu-N from ICN Biomedicals). After this time, the sample was removed and filtered to analyze the water content of the clear solution, which was 130 ppm. Again, 780 g of aluminum oxide was added and stirred for 2 hours. The water content was then 30 ppm.

  The anhydrous solution was separated from the solid by decantation followed by membrane filtration (Alfa Laval's fluoropolymer membrane FSM 0.15PP). The value of water was 35 ppm according to titration in a clear, colorless filtrate (10.1 kg).

Example 5: Pretreatment of LiBOB / PC solution with lithium hydride 1.73 g of LiH powder was added to 210 g of a clear 16% solution of LiBOB having an acid content of 0.3 μmol H ⁺ / g in PC. And stirred for 4 days under air shut-off. After this time, a sample was taken out and filtered through a syringe filter (0.2 μm, PTFE membrane) to obtain a clear solution, and the acid was measured again. Acid could no longer be detected in this sample (≦ 0.01 μmol H ⁺ / g).

  Titration method: against tributylamine in PC, bromophenol blue as indicator.

Comparative Example 1: Recrystallization of LiBOB from acetonitrile (substitution crystallization)
324 g of a clear 20% solution of LiBOB in acetonitrile (AN) was charged to a dry 500 ml double-walled reactor filled with argon. Cool to 0 ° C. with stirring and then add 340 g of toluene dropwise within about 20 minutes. Toluene was first mixed homogeneously with the LiBOB / AN solution. The onset of crystallization was already observed after adding about 50 ml of toluene.

  Stir slowly for about 1 hour at 0 ° C., then discharge the suspension to a sintered glass filter.

  The crude crystals were first washed with 90 ml of toluene and then twice with 50 ml of pentane each time. Subsequently, it was vacuum-dried at room temperature for 2 hours.

  Yield: 63.0 g of crude crystals having an acetonitrile content of 28% by weight.

  The LiBOB • 1.8AN solvate was post-dried in a vacuum drying chamber at 90 ° C. for 24 hours.

Yield: 43.4 g of crystals with a dust fraction of about 40% (67% of theory) (see FIG. 4),
Analysis (ICP): Li ⁺ : 5.10 mmol / g,
B: 5.15 mmol / g.

  The analytical value corresponds to a LiBOB content of 99.4%.

Claims (21)

LiBOB does not contain a solvent that is a foreign substance for the battery, is a coarse crystalline , rectangular parallelepiped LiBOB, and the average value of the maximum diameter of the primary crystals is 50 μm to 5 mm, and the dust ratio is 10 wt% less than forms a dust less LiBOB crystals, this time, dust and has its maximum diameter means 10μm smaller particles and is soluble completely, 15% acetonitrile a 100NTU turbidity at maximum LiBOB solution are present as either one LiBOB · (n5-membered ring ester) complexes, n is characterized by good I 0.001 to 2 equivalents of values der LiBOB.   The 5-membered ring ester is a 1,3-dioxolan-2-one compound, or a plurality of 1,3-dioxolan-2-one compounds, or a γ-lactone, or a plurality of γ-lactones, or at least two of the aforementioned compounds LiBOB according to claim 1, characterized in that it is selected from a mixture consisting of   1,3-dioxolan-2-one compound is ethylene carbonate (EC, 1,3-dioxolan-2-one), propylene carbonate (PC, 4-methyl-1,3-dioxolan-2-one) or butylene carbonate LiBOB according to claim 1 or 2, characterized in that it is selected from (BC, 4-ethyl-1,3-dioxolan-2-one).   LiBOB according to claim 1 or 2, characterized in that the γ-lactone is selected from γ-butyrolactone or γ-valerolactone. The average of the maximum diameter of the primary crystal, wherein a is 00μm~2m m, LiBOB in any one of claims 1 to 4.   LiBOB according to any one of claims 1 to 5, characterized in that less than 20% by weight of LiBOB is less than half the average length of the maximum diameter of the primary crystals. The volume of the primary crystals, characterized in that it is a 0.01~100mm ^3, LiBOB of any one of claims 1 to 6. Dust percentage of LiBOB is characterized and Turkey falls below 5 wt%, LiBOB of any one of claims 1 to 7. Turbidity of LiBOB15% solution in acetonitrile, characterized in that at most 5 0NTU, LiBOB in any one of claims 1 to 8.   The LiBOB according to any one of claims 1 to 9, wherein an organic substance other than a 1,3-dioxolan-2-one compound or γ-lactone is not contained. 11. LiBOB according to any one of claims 1 to 10, characterized in that it does not contain acetonitrile . In a method for producing a crystalline, dust-free and completely soluble LiBOB. (N5-membered ring ester) complex having a residual solvent ratio of less than 50% by mass, crude LiBOB in a solvent for forming a solvate In this case, the solvent contains at least one cyclic 5-membered ring ester as a substantial component, and the particles which are made of the ester and do not dissolve are separated. The clear LiBOB solution obtained therefrom is concentrated by crystallization by evaporation until a solid LiBOB • (n5-membered ring ester) complex is precipitated, and the LiBOB • (n5-membered ring ester) complex is concentrated in the second solid solution. - isolation City by liquid separation step, in which, n is characterized by the Yoiko a value of 0.001 equivalents, less dust crystalline, and complete Method for producing LiBOB · (n5-membered ring ester) complex of solubility. In a method for producing a crystalline and completely soluble LiBOB · (n5-membered ring ester) complex by substitution crystallization, the material contains at least one cyclic 5-membered ring ester as a substantial component, or an ester, a clear solution of LiBOB in a solvent to form a solvate is contacted with a solvent which does not dissolve the LiBOB in pure form, isolated city of LiBOB solvate crystallizes in the course of this mixing, at that time, n is characterized by the Yoiko a value of 0.001 equivalents, crystalline substitution crystallization and to produce a complete dissolution of the LiBOB · (n5-membered ring ester) complexes Method. In the method for producing a LiBOB. (N5-membered ring ester) complex having a residual solvent ratio of less than 50% by mass, crystalline, low dust, and completely soluble, it is crude in the solvent that forms the solvate. A LiBOB crude solution is produced by dissolving LiBOB, wherein the solvent that forms the solvate contains, as a substantial component, at least one cyclic 5-membered cyclic ester or consists of the ester. , separating the undissolved particles, and to precipitate a solid LiBOB · (n5-membered ring ester) complexes of the substituted crystallized from clear LiBOB solution obtained here, the the LiBOB · (n5-membered ring ester) complexes second solid - isolated city by liquid separation step, in which, n is characterized by the Yoiko a value of 0.001 equivalents, residual solvent ratio is 50 mass %, A method for producing a crystalline, dust-free and completely soluble LiBOB. (N5-membered ring ester) complex. In a method for producing a crystalline and completely soluble LiBOB · (n5-membered ring ester) complex by cooling crystallization, at least one cyclic 5-membered ring ester is contained as a substantial component, or the ester A clear LiBOB solution saturated at a specific temperature in a solvent that forms a solvate is cooled to a lower temperature to crystallize LiBOB in the form of a LiBOB. (N5-membered ring ester) complex. , the crystals isolated city, in which, n is characterized by the Yoiko a value of 0.001 equivalents, by cooling crystallization, LiBOB completely soluble in crystalline · (n5-membered Ring ester) complex. 16. A process according to any one of claims 12 to 15 , characterized in that a LiBOB crude solution in a solvent forming a solvate is contacted with a basic compound and / or a solid from which water is removed. 17. The LiBOB crude solution according to any one of claims 12 to 16 , characterized in that it is stirred, shaken or otherwise homogenized with a solid that removes the basic compound and / or water. The method described in the paragraph. Contact time between the LiBOB crude solution and a basic compound and / or solid to remove water, characterized in that it is a 10 minutes to 1 week at a temperature of 0 ° C. to 200 DEG ° C., claims 12 to 17 The method of any one of these. Contact time, advantageously, characterized in that 1 to 10 hours at a temperature of 30 to 200 ° C., any one process of claim 12 to 18. The solid that removes the basic compound and / or water is one or more of the following substances:
Alkali metal hydrides, preferably sodium hydride and / or lithium hydride, metal oxides, preferably calcium oxide, lithium oxalate, lithium hydrogen oxalate, lithium metaborate, lithium tetraborate, lithium carbonate, anhydrous hydroxide 20. Process according to any one of claims 12 to 19 , characterized in that it is selected from lithium, molecular sieves and / or aluminum oxide. 21. A process according to any one of claims 12 to 20 , characterized in that the basic compound and / or the substance for removing water is added in an amount of 0.01 to 10% by weight of the LiBOB solution.

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